"I used to like to hear my father admire the beauty of a flower," wrote Charles Darwin's son Francis, who helped Darwin with botany experiments that led to the discovery of the first plant hormone, auxin. "It was a kind of gratitude to the flower itself - a personal love for its delicate form and colour. I remember him gently touching a flower he delighted in. This sounds sentimental but it was the same simple admiration a child might have. It ran through all his relation to natural things: a most keen feeling of their aliveness."
Why celebrate the 200th birthday of a great scientist who touched flowers like a child? I am no scientist, but I am among Charles Darwin's enormous number of great-great-grandchildren and, to me, his overwhelming feature is his humanity.
In his thousands of letters (now online at www.darwinproject.ac.uk), you see everywhere his energetic curiosity about every life form, and his wonder at all complexity, which I suspect that his granddaughter, my grandmother Nora Barlow, then transmitted both to my mother and to all of us children.
Translated into science, this wondering at complexity went straight into important new concepts still valid today. Biodiversity, for instance, is all about the complexity of relationship. Or take the co-evolution of flower and pollinator. Moths have kept evolving longer and longer tongues in order to drink orchid nectar without rubbing against the pollen.
At the same time, orchids have kept evolving longer and longer nectar spurs, to make the damn moths pollinate them. Darwin, faced with the Madagascan star orchid, which has an amazingly long nectar spur of 28cm, was convinced it had developed through this competitive kind of co-evolution, and predicted that one day a moth with a 25cm tongue would be found: such a pollinator was the only way this flower could possibly get itself pollinated.
People laughed and thought this crazy - but 40 years later, lo and behold, a hawkmoth was discovered, and it did have a 25cm tongue. It was named Xanthophan morgani praedicta in honour of a prediction which came from Darwin's perception that everything in nature came out of relationship. But let's go back to the human.
Darwin had a wonderful sense of complexity in human relations too. He and his wife, his first cousin Emma Wedgwood, both came from very large families; they had 10 children and at least five of these also had large families (hence the numbers of great-great-grandchildren). He also had a huge capacity for affection, an endearing modesty, a naivety people often called childlike, a great anxiety not to give other people trouble, a lively interest in their doings, and a keen enjoyment of tiny things. I think we should do something better in 2009 than just celebrate Darwin. He did not believe in an afterlife and needs no pats from us. "There was something wonderfully exhilarating in his company," says his daughter Henrietta. "He was so vivid, had such joyousness of nature, and his laugh was delightful to hear. His courtesy, tact and ready sympathy made him a perfect listener."
This year is an opportunity to know him better, to spend more time in the exhilarating company of a man who gave us the basis of modern biology and expanded other sciences. "Even if he'd never written On the Origin of Species, geologists would still know him through his work on coral reefs," the geologist Richard Fortey says. "His great book on coral reefs was the first to provide a rational explanation for the formation of reefs. It is still valid today. It was the first example of Darwinian method: testing hypotheses in the field against observations." Then there's psychology.
The only moment in On the Origin of Species when Darwin gets near the question of "Man" is to say, "psychology will now be based on a new foundation: the acquirement of each necessary power".
Thirteen years later he developed that in The Expression of the Emotions in Man and Animals, one of the first books to use the new invention of photography. Since 1838, he had posited an organic basis between our feelings and facial muscles, and wondered if this provided the link between apes and humans.
In 1838, no one else dreamed of going down that path. The first ape seen in London Zoo, in 1835, was Tommy, a chimpanzee - which the zoo dressed in a Guernsey frock and sailor hat. Jenny the orangutan then went on show, also in a frock, in November 1837. But, despite the apes' clothes, despite seeing them using spoons and even drinking tea, everyone ridiculed the suggestion of a shared ancestry; even most naturalists. Queen Victoria called Jenny "painfully and disagreeably human" but no one questioned the moral and mental uniqueness of human beings.
"In nothing does it trench upon the moral or mental provinces of man," declared a newspaper editorial. But Darwin saw in Jenny's face our own same facial muscle movements. If there were the same muscle movements, why not the feelings, too?
In On the Origin of Species, however, he used flora and other fauna, not Man, to demonstrate the principle of evolution. He hated controversy: what he wanted to get across was the principle - that evolution worked by natural selection. The debate about human origins was taken up by younger biologists like T.H. Huxley so that by the time Darwin addressed it in The Descent of Man (1871) all responsible thinkers had accepted evolution - including leaders of the Church.
Lord Harries, former Bishop of Oxford, points out that in 1860 - only one year after Origin came out - a sermon was preached by the Archbishop of Canterbury, Frederick Temple, which effortlessly squared evolution with religion. No problem, said Temple: "Darwin has simply shown us how God moves by natural processes over unimaginably long distances of time." And in the same year Darwin got a fan letter from the devout novelist Charles Kingsley, author of The Water Babies, along the same lines. Evolution? A great idea for Christianity. "Even better than making the world," wrote Kingsley, "God makes the world make itself!"
In 2009, we need to know Darwin better because he is increasingly being identified with one small bit of his work. Ironically for someone who worked by Darwinian method, always led strictly by evidence, always testing ideas in the field, that bit is often called "only a theory". "Something funny is happening to my generation," said my 22-year-old daughter recently. "They seem to think you can choose to believe evolution or not. If people hear I'm related to Darwin they ask, 'do you believe his theory?' They don't object to evolution on religious grounds, they just have an emotional block about accepting that our ancestors were apes. They just don't want to believe that." My daughter is much better at biology than me.
In normal speech, "theory" can mean a guess or unproved fact but even a poet knows that in science a theory is the highest thing there is: a principle, or a law, drawn from a large body of testable evidence. Try telling someone hit by a slate from the roof that gravity is only a theory. For these 22-year-olds, knowledge has regressed 150 years because of the rise of creationism; and the 80s revival of an 18th-century theory ("theory" in a non-scientific sense) called Natural Theology. (It is now called "intelligent design").
But, for 60 years, until the rise of fundamentalism in 1920s America, evolution and religion got on fine. Darwin never said he was an atheist, only agnostic. He had two grounds for objecting to Christianity. One was lack of proof: he was a scientist to his marrow and the one thing he respected was evidence. The other was pain.
"Disease and pain in the world," he noted in 1838, "and they talk of perfection?" He just could not accept the idea of benevolent divinity: he saw too clearly the wastage involved in the way nature worked. "The universe we observe, if properly understood, has all the properties we should expect if there is no purpose, no design, no evil, and no good. Nothing but blind, pitiless indifference. Each form eternally destroyed while others take its place." This observation acquired a tragic resonance in the decade before he wrote Origin.
Twice in those years he watched nature exercise its pitilessness on two of his much-loved children. In 1851 his eldest daughter, sweet-natured Annie, aged 10, fell sick. It was probably tuberculosis but Darwin feared it was hereditary. "It seems an exaggerated form of my illness. She inherits, I fear, my own wretched digestion."
In Malvern, Worcestershire, where he took Annie for a cure, he watched her worsen, and wrote a series of harrowing letters to his wife Emma, who was just about to have their seventh child (my own great-grandfather, as it happens.) "The doctor says there still is hope, but you would not recognise her poor, sharp, hard, pinched face. It is, from hour to hour, a struggle between life and death. God only knows the issue..."
After Annie died, Darwin no longer entered the village church. He left the family at the door and tramped through the lanes, looking for birds. This was when the iron entered his soul. His arguments for natural selection and survival of the fittest were honed as he sorted 20 years of evidence and conducted new experiments in the search for detailed proof, and struggled with his bitter personal experience of these laws. "Nature is prodigal of the forms of life. The fit will be preserved, the weak exterminated utterly - as myriads have been before: battle within battle, ever recurring." He now knew in his own life the pain and loss involved in evolution. The loss not only of species, in millennia of extinctions, but also of individuals like Annie.
"Nature is prodigal of time," he said. "She scrutinises every muscle, vessel, nerve. Every habit, instinct, shade of constitution. There will be no caprice, no favouring." Two years before Darwin wrote On the Origin of Species, he and Emma had a 10th child, Charles Waring, who was almost certainly, four years before John Langdon Haydon Down identified the condition, a Down Syndrome baby. Darwin spent hours with him, watching him crawl elegantly (said the doting father) across the floor: "He will lie calm a long time on my lap looking at my face with a steady, pleased expression, making nice little bubbling noises when I move his chin."
In June 1858, when Charles Waring was 18 months, Charles and Emma watched him die in agony from scarlet fever. "I hope to God," Charles wrote to a friend, "he did not suffer so much as he appeared." All the evidence Darwin had now pointed one remorseless way: "mortal illness in man due, no doubt, to hereditary tendencies towards disease, which clears away the weak." Did his children suffer and die because he had married his first cousin?
"My dread is hereditary ill-health. Are marriages between first cousins doomed to deformity and illness?" On the Origin of Species was written in great haste and sadness and, in some ways, is a very sad book. We are alone with our biology. Our suffering has no consolatory point. But while Darwin wrote it, he knew Emma was mourning their children very differently.
"I feel grateful to God that our darling was apparently spared suffering," she said after Annie died. "I hope I shall be able to attain submission to the will of Heaven." She clung to her faith in an afterlife - and yet she told Darwin not to change one jot of what he thought for fear of hurting her. What I find sad today is that 22-year-olds who identify Darwin with a theory don't understand they are missing out, not just on biology, but on a whole, generous mind, which all can enjoy. I and my daughter happen to be related to Darwin by blood, but he has something for everybody. I have spent most of this year on a book of poems that works like a kind of shorthand biography of Darwin's life and thought. His mother's early death, 8-year-old Darwin's repressing all memory of her, turning to obsessive collecting of newts and stones; the Beagle voyage; the two years of bachelorhood in London while he was secretary at the Geology Society at Somerset House, his mind racing with ideas, himself cantering across London to observe orangutans at the zoo; his nervous proposal to Emma; the children's tragic deaths - and all the way through, his ideas. I am no scientist, I know my poems miss out whole huge, sophisticated, areas of thought. But what anyone can love in him is his love of ideas and his enthusiasm; the way he wonders about connections and processes as well as origins. My prayer is for him to reach those 22-year-olds who hang back from our animal origins.
When Darwin was 22, he was trying to get himself into a hammock for the first time. "I am writing this for the first time on board," he wrote to his sister from the Beagle. "It is now about one o'clock and I intend sleeping in my hammock. Last night I experienced a most ludicrous difficulty in getting into it; my great fault of jockeyship was in trying to put my legs in first. The hammock being suspended, I thus only succeeded in pushing [it] away ... without making any progress in inserting my own body. The correct method is to sit accurately in centre of bed, then give yourself a dexterous twist and your head and feet come into their respective places."
Above all, though, his life is a love story. Thirty years ago, my grandmother, when I was looking after her, talked to me of how difficult it was for the Darwins; that his thinking, in Emma's words, "put God even farther off". I longed then to try and write something about their relationship. This year, doing that work, I realised that, despite a little gulf about God, they had one of the happiest and most honest marriages intellectually, as well as emotionally. And there were, of course, those 10 children. "Oh that I could remember more!"
Emma wrote after he died in 1882. "But it was the same loving gratitude many times a day... The last 12 years were happiest of all, most overflowing with affection." She read to him every afternoon, they played backgammon every night, and they finessed the tough passages with humour. I'm not good at feeling proud of things but in being descended from that pair, what I am proud of is that affection - and their gentle, funny, endearingly modest humanity.
Beneath Darwin's Earth-shaking discoveries lies the private struggle of the man - his loss of faith after his eldest daughter's death, the implications of his theories of existence, and his wife's deep religious sentiment, an opposition that threatens to tear the loving family apart.
In one biopic, Creation (now in production), Paul Bettany plays Darwin and Jennifer Connelly plays the scientist's wife, Emma. Hoping to provide a foil for Creation is a second film, Mrs Darwin, which tells the story from Emma's point of view. Rosamund Pike and Joseph Fiennes are rumoured to be playing the couple, and the film is in pre-production.
* Ruth Padel's book, Darwin - A Life in Poems, is published by Chatto and Windus on Darwin's birthday, February 12.